In the area of photodynamic therapy, TiO2's photocatalytic properties have sparked interest
In food, titanium dioxide is often used as an artificial color additive. Tasha Stoiber, senior scientist at the consumer health nonprofit Environmental Working Group, says titanium dioxide can generally be thought of as a paint primer – it often goes on a hard-shelled candy like Skittles before the color is added to give it a uniform shine.
Food safety experts in the European Union (EU) have recently updated their safety assessment of TiO2 as a food additive. In Europe, TiO2 is referred to as E171, in accordance with European labelling requirements for food additives. The EU expert panel took into account toxicity studies of TiO2 nanoparticles, which to this point had not been considered relevant to the safety assessment of TiO2 as a food additive.
While IARC listed titanium dioxide as “possibly carcinogenic to humans,” they also add that “there is inadequate evidence in humans for the carcinogenicity of titanium dioxide.” Of the four human studies that they reviewed, only one showed a potential risk for occupational workers inhaling titanium dioxide particles and lung cancer, while the other three showed no risk for cancer at all. And it’s key to note that IARC did not assess the effects of titanium dioxide found in foods.